The present invention relates to a novel dye-forming coupler to form an azomethine dye, upon a coupling-reaction with an oxidized product of a developing agent, and to a silver halide photographic light-sensitive material containing said coupler. The present invention also relates to a method for producing an azomethine dye by using the above-mentioned reaction.
In a silver halide photographic light-sensitive material (which may be referred to simply as a xe2x80x9clight-sensitive materialxe2x80x9d hereinafter) using subtractive color processes, a color image can be formed from dyes having three primary colors, i.e. yellow, magenta, and cyan. In color photography using a current p-phenylenediamine-series color-developing agent, a xcex2-acylacetanilide-series compound is used as a yellow coupler. However, the hue of the yellow dye obtained from this coupler is reddish, and it is difficult to obtain a hue of yellow having high purity. This dye has a small molecular extinction coefficient. Thus, in order to obtain a desired developed color density, a large amount of the coupler or silver halide is required. Therefore, the film thickness of the light-sensitive material becomes large, so that the sharpness of a resultant color image may drop. Such problems are caused. Furthermore, the above-mentioned dye is easily decomposed under high temperature and high humidity conditions, and the image storability thereof after development processing is insufficient. Thus improvement in this point is desired.
In order to solve these problems, the acyl group or the anilido group has been improved. Recently, the following have been proposed as improved couplers of conventional acylacetanilide: for example, 1-alkylcyclopropanecarbonylacetanilide-series compounds as described in JP-A-4-218,042 (xe2x80x9cJP-Axe2x80x9d means unexamined published Japanese patent application); cyclic malonediamide-type couplers as described in JP-A-5-11416; pyrrole-2 or 3-yl- or indole-2 or 3-yl-carbonylacetanilide-series couplers, as described, for example, in EP-953870A1, EP-953871A1, EP-953872A1, EP-953873A1, EP-953874A1 and EP-953875A1. Dyes formed from these couplers have improved hue and an improved molecular extinction coefficient, compared with conventional dyes. However, their image storability is still insufficient. Moreover, the synthesis routes of the couplers are long, since their structures have been made complicated. Thus, costs of the couplers are high. For these reasons, the couplers are not practical.
Research Disclosure Item 9939 (page 74, 1972) and JP-A-52-148070 describe couplers having a 2,4-oxazolidinedione structure. However, these couplers are unsatisfactory to solve the problems of the conventional couplers in both hue and a molecular extinction coefficient of the resultant dye.
The present invention is a dye-forming coupler represented by the following formula (I): 
wherein E represents an aryl group or heterocyclic group, or a xe2x80x94C(xe2x95x90O)W group, in which W represents a nitrogen-containing heterocyclic group, Z represents an aryl group or a heterocyclic group, and X and Y each independently represent xe2x95x90O, xe2x95x90S, or xe2x95x90Nxe2x80x94R, in which R represents a substituent, with the proviso that when E represents an aryl group or a heterocyclic group, X and Y each represent xe2x95x90O, and that when E represents a xe2x80x94C(xe2x95x90O)W group, Z represents a substituted aryl group.
Further, the present invention is a silver halide photographic light-sensitive material, which contains at least one dye-forming coupler represented by the above formula (I).
Still further, the present invention is a method for producing an azomethine dye, which method comprises using a compound represented by the following formula (IA): 
wherein EA and ZA each independently represent an aryl group or a heterocyclic group.
Other and further features and advantages of the invention will appear more fully from the following description.